The present invention is directed to a variable-geometry frame which is designed to temporarily support a horizontally disposed plate-like workpiece, such as a sheet of paper or board, that is subsequently to undergo a vertical translational movement between guiding and squaring stops and which frame is located, for instance, within a delivery station were the workpieces are to be piled.
Such a delivery station is located at the end of a die-cutting machine as a last station. A sheet of paper or board, when cut to a proper size and separated from the waste bits, is taken into the last station by a gripper bar in order to be dropped accurately on top of a pile once the gripper bar has been opened or the front waste bit is cut by means of a guillotine.
A sheet can include several blanks arranged side-by-side or successively and permanently attached to one another by linking points. It is absolutely necessary to maintain all the blanks in a plane during the action of the guillotine and to open the supporting frame in a synchronized manner in order to release the sheet which is to drop with a uniform movement.
On the present machines, the process of maintaining the sheets in a plane is achieved by means of a retractable rear shelf as well as one or several horizontal laterally disposed tongues, which are able to pivot with a swinging or mowing movement. Since this type of lateral maintenance holds the blank over a short surface and, in most cases, at inappropriate areas of the sheet, this type of lateral maintenance has proven to be unsatisfactory. One sees too frequently the collapsing of the sheet, the premature separation of the blanks, or even the unsynchronized dropping of the workpieces, which leads to a bad piling up. The production speed and quality are, hence, strongly affected. Moreover, the opening and closing mechanisms of the pivoting supports are relatively complex and, therefore, expensive to manufacture.